Mercury switch



Dec. 12, 1939. c, mns zj v 2,183,198

MERCURY SWITCH Filed June 8, 1937 Patented Dec. 12, 1939 eMERJCURYSWITCH v Alrilr Giver Lindstriim, Stockholm, Sweden ApplicationJune a, 1931, Serial No. 147,093 Sweden June 13, 1936 50laims. (oi.200-152) The present invention relates to mercury switches of the typecomprising a closed receptacle partly filled with mercury, and solidmetallic electrodes therein, said electrodes being adapted to beconnected in an outer circuit and,

inthe closed position of the'switch, to be connected with' each otherwithin the receptacle by direct metallic' gcontact formed by themercury.

Onefobject of the invention is to provide an improved mercuryswitch ofthe type described, in which impurities disengaged from the solidelectrodes due to the action of the electric arc orgoii mercury 'vaporare "prevented from passing tion of the switch, in which the contactgsand breakings are, performed, thus.

maintaining the surface of the mercury in said section clean, wherebythe arc remains easy-to break and excessive heating is prevented even 7'after the switch "has been used for a long period.

Another object of the invention is to prevent the arc and the mercuryvapor from coming into contact with the solid electrodes so as to reduceor eliminate the disengagement of impurities from the latter and todecrease the intermediate resistance between the electrodes and themer-' as mercury filling-openings duringthe assembly I cury.

A further object of theinvention is to pro vide a mercury switch of thetype described, in which the electrodes are screened oil from the freemercury surface in the section of the receptacle, where the contactmakings and breakings are performed, in such a manner that the L passageof particles disengaged from the electrodes to said mercury surface isprevented or made more difllcult.

Still another object of the invention is to provide a switch of the typedescribed having two partitions protruding into the mercury between .theelectrodes and separating the parts of the free mercury surface locatedabove or at the Y electrodes from the parts of said surface locatedmerely with mercury vapor. Provided cenin the space where the contact ismade or broken, in order to retain the impurities on the firstmentionedparts of the mercury surface and to' prevent them from moving therefrom.

A still further object is to arrange said partitions in such a mannerthat a so called mercury trap is formed, by which the gas-fllledspacesnear the electrodes are separated from the remaining gas-filled spaces.v A preferred embodiment of the switch according to the invention willbe described hereinafter with reference to the accompanying drawing, in

i which Figures 1 and 2 are two sectional elevations ,at right angles toeach other, the section accordbetween for tightening purposes.

tres the caps l2 and i3 are pressed out to form-' ing to .Fig. 2 beingtaken along theline 22 in Fi 1. v

In the drawing, I designates a base plate and 2, 3 two resilient armsattached thereto. The

mercury switch proper is rotatably supported by V 5 these arms which bytheir outer ends embrace hollow pivots 6 and l on the switch. The armstubular part being closed by caps 12 and It of any suitable metal, forinstance iron orsteel. The caps are joined to the tubular part by a gomolded mass M, for instance an artificial resin, asbestos rings I5 andIt being interposed there- At theirlcenshort open sleeves" and I8respectively, serving of the switch. The above-mentioned hollow piv ots6 and I embrace these sleeves andare soldered thereto. Preferably, thepivots are made of a highly conductive metal, as'for instance brass, 80

with a viewto ensure a good electrical contact with the arms land 3.Insulating washers l9 are interposed between the sleeves and the brasspivots to prevent thetlatter from being attacked by the mercury. 1

The receptacle thus formed is partly fllled' Y with a mercury mass 20,adapted to form metallic contact between the two electrodes of theswitch, namely the caps l2 and I I. The space ortne receptacle above themercury level may be filled 40 with a suitable gas, for instancehydrogen, or

trally of the receptacle is a wall 2| of insulating material, preferablymade integral with the tubular part II and having an aperture 22 locatedeccentrically in relation; to the axis of rotation of the switch so asto be wholly above the'-mer-. cury level in the one end position of theswitch and immersed in'the mercury, whenthe switch is rocked to itsopposite endposition. Thus, in

the one end position the mercury mass is divided by the "wall 2| intotwo separate halves and' the electrical connection is broken, whereas.in the other endpositioh of the switch theaperture r a: is filledwithmercury, that the whole of me at mercury mass constitutes a coherentunit and forms a metallic connection between the electrodes l2 and I3.

. Provided at each end of the tubular part II is an additional wall 23and 24, respectively, of electrically insulating material, for instanceporcelain, said walls fitting into recesses provided on the innersurface of the part II and joined thereto in a gas-tight fashion. Attheir bottom the walls 23 and 24 have apertures 25 and 26, respectively,which are immersed in the mercury in all positions of the switch, sothat the mercury masses at both sides of the walls are electricallyconnected at all times. Thereby in the operation of the switchimpurities originating from the electrodes I2 and I3 and collected onthe outer surfaces 21 and 28 of the mercury are prevented from passinginto the central space, where the contact makings and breakings takeplace. On account of the walls completely separating the spaces abovethe mercury level from each other, the electric arc is prevented fromreaching. the solid metal electrodes l2 and I3. Due to the restrictedcross-sectional area of the apertures 25 and 26 it is difllcult for themercury vapor to find its way to the electrodes through the mercury.

The embodiment described and shown in the drawing is to be consideredonly as an illustration of the principle of the invention and is notrestrictive of its scope, as modifications in several respects arepossible without departing from the inventive idea as. set forth in theappended claims.

What I claim is: l. A mercury switch, comprising a closed receptaclemounted for rocking movement between two end positions, two electrodesin said receptacle, a mercury mass in same in contact with saidelectrodes, an insulating wall between said electrodes rigidly connectedwith the receptacle, an aperture in said wall adapted on the rockingmovement of the receptacle to be located above the mercury level in oneend position of the switch and under the mercury level in the other endposition of the switch, an insulating wall between each of theelectrodes and the firstmentioned wall, apertures in the last-mentionedWallslocated under the mercury. level in both end positions of theswitch..

2. A mercury switch comprising two metal electrodes, a mercury mass incontact with said electrodes to connect and disconnect the same, anapertured insulating wall between said electrodes to make and break-theconnection between same on rotation of the switch, an insulating wallbetween each of the electrodes and the first-mentioned wall, thelast-mentioned walls being provided with apertures simultaneouslyimmersed in the mercury mass.

3. A mercury switch, comprising a sealed receptacle mounted for rockingmovements. twosulating body, metal caps'closing the ends of said body,an apertured insulating disk located at the centre of said tubular bodyand lateral insulating disks located to both sides of thefirst-mentioned disk and having apertures, said apertures being locatedon the same side of the axis of the tubular body, and means limiting therocking movement of the receptacle.

5. A mercury switch comprising a receptacle consisting of a cylindricalinsulating body mounted for rocking movement aboutits axis, meanslimiting the angle of said rocking movement, two

metal electrodes one at each end of said body, a

mercury mass adapted to connect and disconnect said electrodes, meansadapted to separate and permit coalescence of the mercury mass duringthe rocking movements of the receptacle, insulating disks locatedbetween said electrodes one at each end of said cylindrical body, said dsks being provided with apertures located on the same side of the axisof said cylindrical body.

ALRIK CIVER LINDSTRCSM.

